Flocculation, Reflocculation and Overflocculation

[drycreek]

So I recently had my first green algae bloom after my two large live oaks dropped their pollen this spring. So I added a dose of Diclor, filtrated for two hours to mix then added a flocculant and mixed for two hours. The next morning the dichlor and floc had done a fantastic job. The algae was dead as a door nail and flocced and dropped to the bottom of the pool.

Now came the hard part, getting the dead algae out of the pool.

I vacuumed most of it out but in the process (about a week long) I ended up stirring up the flocculated dead algae. So while the pool looks much better it still has a cloudy hew to it. I've let it sit and the flocced algae still creeps to the bottom and I'll vacuum again when it seems appropriate.

My questions for the forum are this:

1. Should I/could I add more flocculant now that it's been a week to makes sure all the suspend dead algae is clumped and dropped to the bottom of the floor? Or just be patient with the dosage I've already used?
2. Overflucculation. Is there such a thing and what could/would the dangers be?

This is my first post so thanks for your replies in advance!

Happy Swimming!

Drycreek.

 

[YippeeSkippy]

Howdy Drycreek Welcome to TFP

Floc and clarifyers aren't something we recommend generally. They can cause filter problems.

We believe in only adding chemicals to our pools based on our own accurate testing. We don't trust pool stores testing (as they often quite inaccurate as well as having a sales focus behind finding problems) so I can't really advise you what to do about the Floc.

These are the only chemicals we deem necessary for routine pool care: Pool School - Recommended Pool Chemicals

Please consider reading our methods of pool care under the PoolSchool Link at the top right.

Yippee

 

[Donldson]

Welcome to TFP!

I don't have much time but wanted to comment, the reason your water is clouding back up is because you didn't eliminate all of your algae. The dichlor hurt it some, though if you regularly shock with dichlor your water may be overstabilized, and the floc let you vacuum quite a bit out, but there was plenty of algae left in and is growing again.

You mentioned this is the first bloom, do you mean ever or of the season?

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[drycreek]

Welcome to TFP!

I don't have much time but wanted to comment, the reason your water is clouding back up is because you didn't eliminate all of your algae. The dichlor hurt it some, though if you regularly shock with dichlor your water may be overstabilized, and the floc let you vacuum quite a bit out, but there was plenty of algae left in and is growing again.

You mentioned this is the first bloom, do you mean ever or of the season?

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Sorry, yeah we moved into the house last July with the pool already in. We've had several hard rains and our pool stays pretty balanced so this was our first algae bloom. The oak pollen drop is the only thing that's caused it to bloom so far.

The haziness is not algae still growing. There's no way. At least I highly doubt it. My TC and FC are at 5 ppm and my PH is 7.2


That's a really hostile environment for algae. Virtually no chance for it to live in that.


Like I said, I've just stirred up the existing dead algae during the vacuuming process and that's what's causing the cloudiness. If the pool is still for a long time without running the filter at all or trying to vacuum then it's extremely clear and all the flocced algae will fall to the bottom of the pool again.


Again, my question is whether or not to use another dose of flocculant.


I understand TFP's position on chemicals but flocculants are regularly used the world over to sequester colloids and purify water. They work great for swimming pools too.


I'm just wondering if anyone here has had any experience with "reflocculating" or "over flucculating".


Thanks so much for the replies.

 

[YippeeSkippy]

Actually a FC of 5 and pH of 7.2 is nothing very hostile at all, especially if ones CYA was high. We dose our pools FC based on the CYA level.

See this link--> [FC/CYA][/FC/CYA]

Pool pH normal acceptable range is 7.2-7.8.

Yippee

 

[drycreek]

Actually a FC of 5 and pH of 7.2 is nothing very hostile at all, especially if ones CYA was high. We dose our pools FC based on the CYA level.
See this link--> [FC/CYA][/FC/CYA]

Pool pH normal acceptable range is 7.2-7.8.

Huh?

The IPSSA recommend FC range for an inground swimming pool is 2-4 ppm (NPC recommends 3-5 ppm) meaning, apart from a large dose of colloids/bateria (like my algae bloom), 2-4 ppm (or 3-5 ppm) FC should kill most undesired colloids/bateria. Meaning 2-4ppm FC is hostile to colloids/bateria. When I shocked my pool with Dichlor my FC was up around 7.5 ppm and my TC was at 10 ppm. So near the max they really should be.

NPC recommends 7.2 to 7.6 on PH otherwise you're LSI will be out of the 0.0 to +0.3 range and your water will have corrosive or scaling tendencies. I'm at 7.2, don't want to be much lower than that or my LSI will dip below zero creating a corrosive environment.


As an update, since I initially posted this the water has gotten clearer and clearer as all the flocced algae has again settled to the bottom of the pool. I guess I won't flocc it again as the initial dosage appears to still be working really well. It's just the vacuuming and filtration tends to stir of the environment and cause the cloudiness. Nothing I can do about that until most if not all the dead algae is gone via vacuuming and filtration.

Thanks for you help.

 

[Donldson]

Those numbers you are quoting assume zero CYA. Since you are using dichlor you have CYA in your water, which is affecting your chemistry. What is your CYA level?

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[pabeader]

Drycreek - You might find this interesting: Certified Pool Operator (CPO) training -- What is not taught

 

[JoyfulNoise]

Other have and will advise you on proper pool chlorination, I'm not going to beat that drum anymore. So, since you asked the question, let me answer it - yes, you can "over-floc" a pool.

In fact, this is most often the problem that occurs with pool owners and floc - they fail to follow the directions, fail to adjust their water chemistry to the appropriate levels and then use the old adage, "If a little is good, then A LOT MORE MUST be better!! Yee-haw!!" If you add too much flocculant to a body of water, the floc, which is typically cheap aluminum sulfate, will actually agglomerate not with the particles you are trying to remove but the floc itself. It will then stay suspended in the water column instead of dropping and you will completely plug up a filter trying to clear it. Aluminum floc's form aluminum hydroxide which, in water, created a polymeric-like structure (think of it like a gel) that attaches to particulates and causes them to drop. In doing so, the sulfate part of the floc forms sulfuric acid which is why one typically needs to raise the pH before adding floc in order to avoid an aggressive drop in pH. The problem with these types of floc's is that they also add sulfates to the water which is bad for cementious surfaces (sulfate attack) and will destroy SWG cells because the plate coatings get eaten away by the sulfates.

Since one can achieve a clear pool with nothing more than chlorine and proper maintenance, why would one ever want or need to use a floc? Yes, flocs are used in other water applications but your pool is not a drinking water source nor is it source of boiler water or cooling tower water or part of a waste treatment facility that converts waste water into discharge water. It's a pool, something you swim in, and many of us prefer not to lard it up with lot's of chemicals it does not need. Flocs are a cheap and easy way to make a body of water appear clear for a short period of time but, as we say all the time here, clear water is not a sign of clean water.

 

[Rollercoastr]

Out of curiosity, I googled "IPSSA cyanuric acid". I didn't see any hits on their site about the relationship between chlorine and CYA. (but it did return an interesting article about it from NSF International - a very bright group of people in my hometown)

I'm still confused why the pool community so rarely discusses it. I can see why pool $tores fear a different way of thinking, but why do independent organizations?

 

[drycreek]

Those numbers you are quoting assume zero CYA. Since you are using dichlor you have CYA in your water, which is affecting your chemistry. What is your CYA level?

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No, NPC calls for 30 to 50 ppm CYA. I'm at 30 ppm.

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Looks great, I'll have to wad through it when I get some time this weekend. Thanks!

- - - Updated - - -

Other have and will advise you on proper pool chlorination, I'm not going to beat that drum anymore. So, since you asked the question, let me answer it - yes, you can "over-floc" a pool.

In fact, this is most often the problem that occurs with pool owners and floc - they fail to follow the directions, fail to adjust their water chemistry to the appropriate levels and then use the old adage, "If a little is good, then A LOT MORE MUST be better!! Yee-haw!!" If you add too much flocculant to a body of water, the floc, which is typically cheap aluminum sulfate, will actually agglomerate not with the particles you are trying to remove but the floc itself. It will then stay suspended in the water column instead of dropping and you will completely plug up a filter trying to clear it. Aluminum floc's form aluminum hydroxide which, in water, created a polymeric-like structure (think of it like a gel) that attaches to particulates and causes them to drop. In doing so, the sulfate part of the floc forms sulfuric acid which is why one typically needs to raise the pH before adding floc in order to avoid an aggressive drop in pH. The problem with these types of floc's is that they also add sulfates to the water which is bad for cementious surfaces (sulfate attack) and will destroy SWG cells because the plate coatings get eaten away by the sulfates.

Since one can achieve a clear pool with nothing more than chlorine and proper maintenance, why would one ever want or need to use a floc? Yes, flocs are used in other water applications but your pool is not a drinking water source nor is it source of boiler water or cooling tower water or part of a waste treatment facility that converts waste water into discharge water. It's a pool, something you swim in, and many of us prefer not to lard it up with lot's of chemicals it does not need. Flocs are a cheap and easy way to make a body of water appear clear for a short period of time but, as we say all the time here, clear water is not a sign of clean water.

[FONT=verdana, arial, tahoma, calibri, geneva, sans-serif]Thanks for the great reply. All good points. So to be sure I understand you correctly, in short, why use a floc to group and drop the dead algae? Just kill the algae with chlorine and then filter it out. All the floc does add "gunk" if you will to the bad stuff and cause a whole host of problems with your filter and SWG.[/FONT][FONT=verdana, arial, tahoma, calibri, geneva, sans-serif]
[/FONT]
[FONT=verdana, arial, tahoma, calibri, geneva, sans-serif]Makes a lot of sense. So if I have a bloom again I need to just shock it with Diclor and then filter it out. May have to rinse the filter 4 or 5 times but that should do it correct?[/FONT]

 

[madwil]

Dichlorvos will add more cya. If you need to add chlorine just use bleach or liquid chlorine. If you drive the cya up it'll just make it harder to clear in future.
If you maintain your fc according to the cya chart you probably will never need to shock or slam again

 

[drycreek]

Out of curiosity, I googled "IPSSA cyanuric acid". I didn't see any hits on their site about the relationship between chlorine and CYA. (but it did return an interesting article about it from NSF International - a very bright group of people in my hometown)

I'm still confused why the pool community so rarely discusses it. I can see why pool $tores fear a different way of thinking, but why do independent organizations?

Not sure on that. May not be posted on line but this 2016 training manual goes into detail about it...

 

[pabeader]

You definitely need to read the link I posted earlier.

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Oh I almost forgot. Once you start following the TFP way of pool care, blooms will be a thing of the past.

 

[JoyfulNoise]

Not sure on that. May not be posted on line but this 2016 training manual goes into detail about it...

You'll find that Richard Falk (aka, chem geek) and Lowry corresponded about the effects of CYA - Certified Pool Operator (CPO) training -- What is not taught - Page 2 Chem Geek has, beyond anyone else here, moved mountains to try to get the industry to recognize the FC/CYA relationship. Your 2016 materials contain information found here - http://www.lowrycg.com/wp-content/uploads/2013/05/Cyanuric-Acid-It-Controls-Your-Pool-rev03.pdf where Lowry explicitly states the 7.5% FC/CYA ratio as the minimum ratio needed to keep a pool sanitary. This FC/CYA ratio was deduced by Richard Falk and the previous work done by Ben Powell at The Pool Forum well over a decade ago. In fact, it was Ben Powell who first realized through his commercial pool management business that pools which tightly controlled their CYA levels suffered far fewer problems than pools that did not. It was his initial work that piqued Richard's chemistry curiosity (Richard is not actually a chemist by training but has degrees in chemistry from his college days) and the two together figured out the FC/CYA ratio long before the industry ever cared about it.

You'd do well to cross-reference anything you read in that manual with TFP as it is very likely Richard was writing about the topics well before anyone in the industry took notice...

 

[Rollercoastr]

Not sure on that. May not be posted on line but this 2016 training manual goes into detail about it...

Wow - proof that the pool community (if not industry) has taken a major step forward.

 

[Swampwoman]

Dry creek, I once used a floc-like substance for a completely different and experimental purpose on which I won't elaborate here.

But in answer to your question:

I'm just wondering if anyone here has had any experience with "reflocculating" or "over flucculating".

:

-- if its not all been caught by your filter by now, turn your pump off overnight to let it resettle to the bottom (up to 24 hrs again)...then using the manual vac that attaches to skimmer (robots will just break it up and recirculate) and vacuum VERY SLOWLY to waste. Next day, rinse and repeat as they say.

In my experiment, it took me about a week to get it all.

Which is why of course, in the case of algae, its much simpler to just SLAM Process the TFP way -- one reason of many
(My experiments were not related to algae but were attempts to clear some really old water from constant sequestrant use in a metal/iron battle connected to my well.)

 

[Sr. Notso]

So, also had a algae flare up. Excessive rain water added to pool over winter, chlorine got low, added some Cutrine algaecide, then made bad choice of "floc"! Ouch, waited too long to vac, now have floating white stuff. Need to clean D.E. filter.
But was wondering, why spend $$ to add more chemicals, when I could just drain, clean pool bottom and refill? Why do I see the recommendations to add additives when draining and refilling seems easier/faster? $50.00 worth of water vs aggravation?

 

[YippeeSkippy]

So, also had a algae flare up. Excessive rain water added to pool over winter, chlorine got low, added some Cutrine algaecide, then made bad choice of "floc"! Ouch, waited too long to vac, now have floating white stuff. Need to clean D.E. filter.
But was wondering, why spend $$ to add more chemicals, when I could just drain, clean pool bottom and refill? Why do I see the recommendations to add additives when draining and refilling seems easier/faster? $50.00 worth of water vs aggravation?

We don't recommend algaecides, and they don't kill an algae outbreak. They act as preventative measures. We feel that if you just keep your pool properly chlorinated you don't need them. And cheap versions often have copper in them which causes mucho problems.

Some folks have to work with the water they have. Either their wells won't support a total drain and refill or water prices are out the roof high. If your pool only costs $50 to drain and refill... why didn't you do that instead of adding all that algaecide and floc? LOL.

Yip

 

[JoyfulNoise]

Draining can also be problematic for some pools. You can't ever fully drain a vinyl pool as the liner will shift, crease and never go back to its original form.

Some people have high water tables and fully draining a pool can cause it to pop out of the ground.

A plaster pool can/should only be drained when the air temps are lower than 85F and need to be refilled right away or else you risk plaster cracks.

Also, draining doesn't solve a bad algae problem. Algae will hide in almost any part of the pool (light niches, plumbing, etc). So there's no effective way to drain and clean out all of those areas.

Finally, you're talking about discharging tens of thousands of gallons of water. Some people live in neighborhoods where that would be impossible to do without possibly incurring fines or they simply don't have a place to drain that much water.

Draining a pool is a last resort and is almost never a good way to solve any pool problem.


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